Subcaliber attachment for guns



Dec. 28, 1948. J. M. DIAL SUBCALIBER ATTACHMENT FOR GUNS Filed Feb. 8, 1946 IN VEN TOR.

diam. I22;

Patented Dec. 28, 1948 or ies James-M:-

'E QHEKT EQRHGIW J Dial-,Daytgn, Ohio.

ripp lieatioir fiepgqar w, 1946, Serial No. 646,399

13- Claims. 1:

T e es nt. n e t qn re tes. R 9 arms and more partienlarljtoja s ipoalipe r; at; hm n f r in tm i r lai e Pi w c n u h 'i i j iei iiqe snell;eelifi%% sueh'asarifie.

Principal objects of I vide an attachment of the type will be simple and inexpensive to Will be capable, of bei g in r L i l asi wh W 11. e we sirilcfion' d r le ilsi qo i g sgwlai ii Will be applioablefto a wider ng'e of shotgnntypes and kinds, which will nnfa'il eject 10W: caliper cartridge. shells 'reg'ard'l" f 3 whether the shotgun, is provided with an eetpror Whether the shot gun ejector is operating, high will; be se;

m itivent qn r ary: "X -Wh h, fwhi h.

curely maintained inoperative and pregle aligned position in the sho b rzjel w T be adjusted through wide e {Isle 1r tions in thes hotgnn barrel t gopggensat for Wear, i e i th 'vbp an si ts. as? d h h i l ha e um qua ether 9 further v ta s. ei lw lib Q ent present description and illns tr s of an en o imeni f he nven n 15 aie i ii tested in aetual pract U and hi w I tl' 1e r e0re pre e nd ha e 91 .9. 9. illustrate-tee 2 11 ciples of the inve nti o N In the accompanying drawing, which trates the preferred embodiment i u e 1 fa iee vw jii aallv ew o a hgii n in opened position, showin'gthe s paliherat i c i n cwliili i? i999 li-m i lilh extended;

FigfZ is aside elevation l view, ona relati vely enlarged scale, of the att a' n ent;

Fig 3 is a rear end elevation'aljview of-the attachment;

' Fig. 4 is an axialsectionalview;

Fig. 5 is a erossseletioj'nalfi ieyv talienon tl' e line 5-5 of Fig. 4; j

Fig. 6 is a side elevationalyiew 01? a tool used for withdrawing the attachment from the shotigun barrel; and

Fig. 7- is a cross sectional-view talgenon the line 7-'! Of Fig. 2. k 7

While the principles ofi the invention are appli; cable, without essentiaL change, to numerous types and kinds o f firear ns, the'inyention is par ticularly useful'for converting-any type of shotgun into a small ealiloer rifle, and itis'inthisfeinbodiment that-the invention will bedisclosed in the present application for;Letters; IE -etent In' Fig. 1; a conventional type ofshiqtgurn is e i d. en c nd -i q a t e r f reeie a'fezjirard p 2 numeral I; a portion of tlie stoolgbeing shown at; 2; 'and 3iindie'alting a fiort ipn of fth ba rrl attaehment-bijovided y the present intention is designated-generally ifandcoi niirises a gif riinetal} barfl "efnberhavii ig a rear ortion ear-by indncal 'gea e properly diirienslioned' td with cIeaianQ Or fiIajI iii'therqr portion of the: bore" or 'the finp chamb'r of the merger; with; whichf'the':'attaohinent is intended" to' wage;- eman tes a integral -with this rear portion is ortion 65 0i reducedfoiitsidedianieterl a tendances tore i 'e'itendsaxjally'thi oiighthe; entire'hai'rel iniriher aridgtfirs'boremasfbe time a r the rorwa'rd pd epife spa radially enlarged and shoiildered its" rear: portion to'pr ov ide" a fifingfiha niberfl forl a small caliber cartridge 9; whieH/rfiai} be a cartridge oil-standard The barrelfinember'4 isliritridedtobe inserted means into't'he' shotg" barrel ramme rear bie'eclitliei eoHwhfe can'beieadiW done the'jgii n ism opened-position," as shown Fig; 'lifhit 'th' fin'etratiofi' oi the barrel inemloer into the Bore, "the rear" nortio'n '5 6f the barrel n'iinbr stra -end with a pe rinherali'bead or enlargement l'q which s tsagainst theresurface offth'efshotgun barrel intl iesaine insr meija' dbeg ajshqtgii'n shell of'a"aliber' 'abbropriate" for the augepr-pne'snot un 'Asf'show'n in Fig'ffi, a segment of-the beador enlargement l0 is removed through afiqxtentgpf sumewhat l ss than-180"; fria s Iililh asf ii iaj be necessary to avoid engagement of 'the'beald in y tlie ejector 13 7 ejegtcsr finger: (not s own) ordinarily provided-011 liiq s t shotgunsl' I'n apart ventionail type of double-loarreled] shotgun there are tworsnch ejeetor f ngers or two portionsof a sing-le finger, one proyide'cbfor eaeh'of-the two barrels. In the 'do'ublebarreled 'shotgun1 selected =t9 illuis trate'tlie' present invention; "a single low caliber attachment' is shown installed in the leftbarrelof the-gun, and the bead-40 1s removed aronndv-aportion of-its righthancl and-loWer sides because it 'is this'portion which is adjacent-tothe ejector finger or finger portion of;such a'gun For use iilsingle harrel'ed shotguns; or guns. having ejeetor fingers otherw ise lecated; a differentseg 3 radially into the firing chamber 8 and contains an axially slidable ejector block l2 which has its upper surface cylindrically concavely curved as shown at l2a to supplement that part of the firing chamber 8 which is formed by the metal of the rear portion and to cooperate with it to complete a chamber for the cartridge 9. The rear surface of the block is fiush with the rear surface of the portion 5 and is radially extended at is to form a continuation of the bead [0 of the portion 5. It is this block bead l3 which is positioned to be engaged by the extractor provided on the gun, so that actuation of the extractor will pull the block l2 sufficiently back out of the recess II, as to the dotted line position shown in Fig; 4,

' curely mounted in the shotgun bore, I prefer to firing chamber.

The axis of the firing chamber is located eccentrically of the rear portion 5 of the barrel member, and the member is so mounted in the shotgun barrel that the firing pin (not shown) of the gun, which is arranged to strike the center of a shotgun shell, will strike a point on the rim of the low caliber cartridge 9. This arrangement is made necessary by the fact that most low caliber cartridges are of the rim-firing type and because it is this type of low caliber cartridge that is intended to be used in the present attachment.

The forward portion 6 of the attachment has an outside diameter which is considerably less than the inside diameter or bore of the shotgun barrel. This difference in diameters, combined with a slight diiference between the outside diameter of the rear portion 5 of the attachment and the inside diameter or bore of the shotgun firing chamber in which the portion 5 is positioned, permits the attachment to be rocked slightly through an angular adjustment in the gun bore so as to vary the relationship of the axes of the attachment and the gun barrel. The relationship may be made variable between one of parallelism of the axes to one in which the axes are angularly separated in any direction sufliciently to compensate for any uneven wear of the shotgun bore or any imperfection of the gunsights. This makes it possible to mount the barrel member in the gun bore in such a way that the attachment axis will be properly related to the gunsights for accurate firing.

In order to calibrate the attachment by fixing the relative angle of the axes of the barrel member 4 and of the shotgun bore at any required correct value, the-forward portion 6 of the barrel member is provided with a peripheral flange or enlargement M in which are set, at peripherally spaced intervals, a plurality of headed machine screws or studs l5. In the illustrated embodiment of the invention four such screws are used, at intervals of 90 around the flange M. The head of each of these screws is provided with two, three or more small transverse holes through which a locking wire I6 may be passed. It willbe evident that by turning the screws in their tapped openings in the flange l4 they may be individually set at any degree of radial projection and that all the screws may be locked in their positions by passing the single wire [5 through those of the holes in the screw heads which happen to be peripherally aligned. In setting the attachment for accurate firing, the barrel member is mounted in the shotgun bore with the screws l5 set at some trial adjustment. The gun is fired and any deviation causing the bullet to miss the target is noted. The attachment is removed and compensation is made to the right or left, or up or provide a leaf spring 11 which is bowed radially outwardly between the flange l4 and a boss I8 15' formed at the forward end of the rear enlargement 5. This spring may be held on the boss 18 by a small U-shaped clip 19 which is screwed to the boss and straddles the spring near its rear end, and the forward end of the spring is received in anyone of a pair or more of radially spaced notches 20, 20 provided in the rear face of the fiange l l. Fig. 2 shows in full and dotted lines how the spring I! can be adjusted to project radially a greater or less extent and bear more or less forcibly against the lower portion of the shotgun bore so as to urge the forward portion 6 of the barrel member'more or less firmly up against the upper portion of the shotgun bore.

For use in shotguns provided with an ejector, it isdesirable to have the block I! yieldably urged to its forward or inner position, so that on release by the ejector the block will move from its dotted line position of Fig. 4 inwardly to its full line position. For use in guns not provided with an ejector, or in guns having a broken or otherwise inoperative ejector, it is desirable to have the block I2 yieldably urged outwardly to its dotted line position of Fig. 4. In this Way the cartridge 9 will be ejected automatically when the gun is broken to the open position shown in Fig. l, and after a new cartridge has been inserted in the firing chamber while the block is thus rearwardly projected, the block will be restored to its forward position automatically, when the gun is closed, by the pushing force of the gun breech member 2| against the rearwardly projected block.

These alternative arrangements are provided by the simple mechanism which will now be de scribed.

From the forward end of the block l2 a stem 22 projects through a rear guide bearing 23 and a forward guide bearing 24, which are spacedapart along a line parallel to the axis of the barrel member and radially down below the outer wall of the reduced forward portion of the barrel member, although within the cross sectional area of the enlarged rear portion 5. The rear guide bearing 23 may be formed in what is in effect the front wall of the rear portion 5, and the forward guide bearing 24 may be formed in the boss 48. A coil spring 25 is wrapped around the stem between the two guide bearings, and a lug or stop 26 may be pinned to the extreme forward end of the stem 22, forwardly beyond the forward guide bearing 24. The function of this lug, which is square or otherwise polygonal in shape and is located so close to the barrel that it cannot turn, is to prevent such rotation of the stem 22 as might unscrew the stem from the block [2.

If it is desired to, havethe block I2 yieldably urged to forward position, the spring 25 is compressed between the rear guide bearing 23 and a pin 21 (Fig. 2) passed through a forward hole 28 (Fig. 4) formed through the stem 22. A washer 29 may be interposed between the pin 21 and the spring, and it will be obvious that this spring, acting in tension between the pin 21 and the rear guide bearing 23, will yieldably urge the block l2 to its forward limit in which it is seated in the recess H, in the full line position of Fig. 4.

If is it desired to have the block l2 yieldably urged rearwardly, to its dotted line position in Fig. 4, the pin Zl is removed from the opening '28 and inserted in a rear opening 30 (Fig. 4) formed through the stem '22 near the rear guide bearing 23. The washer 29 may be interposed between the pin in this position and the spring, which is now compressed between this pin and the forward guide bearing 2d. The spring, under compression, urges the block ['2 rearwardly to its dotted line position of Fig. 4, and this arrangement causes the block to eject the cartridge 9 automatically when the gun is opened to the position shown in Fig. 1, without reliance on any ejector finger.

It may be found desirable to protect the forwardly projecting end of the stem 22 by providing a sheet metal or stamped guard 3| to cover the end of the stem between the clip 19 and a point beyond the end of the stem where the guard can be fastened to the barrel member by a machine screw 32. This will prevent distortion of the stem in case the leaf spring I! should become inwardly instead of outwardly bowed.

In order to facilitate extraction of the attach ment from the bore of the shotgun in its convenient to form a more or less radial recess or hole 33 in the wall of the firing chamber opposite the slidable block i2. A hooked tool 34, shown in Fig, 6, may be inserted into the opening 33 so that the attachment can be readily withdrawn from the gun bore.

, It is found in actual practice that with the spring ll properly adjusted to press radially outwardly with appropriate pressure, the attachment is held in predetermined position in the shotgun bore and that it does not tend to rotate therein despite any amount of firing and rough handling. In this way the alignment of the attachment and gunsights to which the screws have been adjusted is preserved.

After the attachment is withdrawn for any reason, as for example in order to use the gun bore for the firing of shotgun shells, the attachment can be unfailingly restored to the same position at which it was previously set in the gun bore by orienting the bead t0 and its cut-out segment in the same way as before with relation to the shotgun shell ejector. This is easily accomplished by taking care to set such a shoulder as is shown at 3 at one end of the cut-outsegment, against the path through which the ejector or ejector finger moves. Any other reference point may be employed for assuring identical repositioning of the attachment after it has been properly adjusted and then removed, such, for example, as a line inscribed radially on the rear face of the rear portion 5 of the barrel member and a similar line inscribed on the rear face of the shotgun barrel. The attachment can then be set, by adjustment of the screws I5, with these two lines in registry or alignment, and it can always be repositioned to the same settin by replacing it in such a way that the two lines are registered or aligned.

It is believed that the essential principles of the invention will be clear to those skilled in the art from the foregoing description of a preferred embodiment. Other and further modifications of the invention are contemplated, and all of them,

6 to the extent that they embody the principles of the invention as pointed out in the appended claims, are to bedeemed within the scope and purview thereof.

I claim:

1. A subcaliber attachment for the barrel of a gun comprising a barrel member receivable in the-gunbarrel, means provided at the rear end of the barrel member for limiting insertion thereof in the gun barrel, and a. plurality of peripherally spaced screws threaded into the barrel member forwardly of the rear end thereof and radially adjustable to engage the bore of the gun barrel to regulate the position of the barrel member axisfrelfatively to the gun barrel axis.

2.-A-subcaliber attachment for the. barrel of a gun comprising a barrel member receivable in the gun barrel, means provided at the rear end of the barrel member for limiting insertion thereof in the gun barrel, a plurality of peripherally spaced screws threaded into the barrel member forwardly of the rear end thereof and radially adjustable to engage-the bore of the gun barrel to regulate the position of the barrel member axis relatively to the gun barrel axis, and means for holding the screws in adjustably selected positions.

3. A subcaliber attachment for the barrel of a gun comprising a barrel member receivable in the gun barrel, means limiting insertion there of in the gun barrel, and resilient means projecting from one side of the barrel member against the adjacent surface of the gun barrel bore so as to urge the barrel member securely against an opposite portion of the gun barrel bore sur face and tend to hold the barrel member in such position.

4. A subcaliber attachment for the barrel of a gun comprising a barrel member receivable in the gun'barrel, means limiting insertion thereof in the gun barrel, and adjustable resilient means projecting in a generally radial direction from the barrel member into contact with the gun barrel bore so as to urge the barrel member of an 'adjustably selected pressure against an opposite portion of the surface of the gun barrel bore.

5. A subcaliber attachment for the barrel of a' gun comprising a barrel member receivable in the gun barrel, a block slidable axially in the rear portion of the barrel member and cooperating therewith to form a subcaliber firing chamber, spring means urging said block forwardly in the barrel member, and a peripheral enlargement formed on the 'rear end of the block adapted to be engaged by the ejector of the gun so that said ejector may slide the block rearwardly, against the action of the spring means, and withdraw a small caliber cartridge shell from the firing chamber.

6. A subcaliber attachment for the barrel of a gun comprising a barrel member receivable in the gun barrel, a block slidable axially in the rear portion of the barrel member and cooperating therewith to form a subcaliber firing chamber, a spring reacting between the block and the barrel member for urging the block forwardly in the barrel member and aligning the rear face of the block in the same plane as the rear face of the barrel member, and a projection formed on the block for cooperation with an ejector provided on the gun for sliding the block rearwardly against the action of the spring to withdraw a small caliber cartridge shell from the firing chamber.

' ,7. The combination claimed in claim 6, including a stem forwardly extending from the block, a pair of spaced guide bearings for the stem formed on the barrel member, and a coil spring Wrapped around the stem having its forward end fastened to the stem and having its rear end reacting in compression against the rearmost of the pair of guide bearings for urging the block forwardly in the barrel member.

8. A subcaliber attachment for the barrel of a gun comprising a barrel member receivable in the gun barrel and having a rear portion substantially the diameter of the gun firing chamber so as to make relatively snug fit therein and having a forward portion of reduced diameter, a radial enlargement formed on the rear end of the barrel member for limiting insertion thereof in the gun barrel, a peripheral flange projecting radially from the forward portion, and a plurality of peripherally spaced screws threaded into the forward portion at the zone of the flange thereof for radial adjustment to engage the bore of the gun barrel to regulate the position of the barrel member axis relatively to the gun barrel axis.

9. A subcaliber attachment for the barrel of a gun comprising a barrel member receivable in the gun barrel and having a rear portion substantially the diameter of the gun firing chamber so as to make relatively snug fit therein and having a forward portion of reduced diameter, a radial enlargement formed on the rear end of the barrel member for limiting insertion thereof in the gun barrel, a peripheral flange projecting radially from the forward portion, a plurality of peripherally spaced headed screws threaded into the forward portion at the zone of the flange thereof for radial adjustment to engage the bore of the gun barrel to regulate the position of the barrel member axis relatively to the gun barrel axis, and a wire inserted through holes in the heads of said screws to maintain them in predetermined radially adjusted positions.

10. A subcaliber attachment for the barrel of a gun comprising a barrel member receivable in the gun barrel, a block slidable axially between fixed limits in the rear portion of the barrel member and cooperating therewith to form a subcaliber firing chamber, a stem extending forwardly from the block, a pair of spaced guide bearings for the stem formed on the barrel mem her, a coil spring wrapped around the stem between the guide bearings, and means connecting the spring to the stem under compression between the stem and one of said guide bearings for urging the block against one of its fixed limits.

11. A subcaliber attachment for the barrel of a gun comprising a barrel member receivable in the gun barrel, a block slidable axially between fixed limits in the rear portion of the barrel member and cooperating therewith to form a subcaliber firing chamber, a stem extending forwardly from the block, a pair of spaced guide bearings for the stem formed on the barrel member, a coil spring wrapped around the stem between the guide bearings, and means compressing the spring between the rear guide bearing and a point on the stem between the guide bearings so that the spring yieldably urges the block against its forward fixed limit.

12. A subcaliber attachment for the barrel of a gun comprising a barrel member receivable in the gun barrel, a block slidable axially between fixed limits in the rear portion of the barrel member and cooperating therewith to form a subcaliber firing chamber, a stem extending forwardly from the block, a pair of spaced guide bearings for the stem formed on the barrel member, a coil spring wrapped around the stem between the guide bearings, and means compressing the spring between the forward guide bearing and a point on the stem between the guide bearings so that the spring yieldably urges the block rearwardly to its fixed limit.

13. A sub-caliber attachment for the barrel of a gun comprising a barrel member receivable in the gun barrel, a block slidable axially between fixed limits in the rear portion of the barrel member and cooperating therewith to form a subcaliber firing chamber, a stem extending forwardly from the block, a pair of spaced guide bearings for the stem formed on the barrel member, a coil spring wrapped around the stem between the guide bearings, said stem being provided with spaced holes between said guide bearings, and a pin insert'abl-e alternatively through any of said holes provided in the stem between the guide bearings, whereby the spring may be compressed between the rear guide bearing and the pin inserted in a forward hole to urge the block forwardly or between the front guide bearing and the pin inserted in a rear hole to urge the block rearwardly.

JAMES M. DIAL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 611,062 Darms Sept, 20, 1898 631,399 Gillette Aug. 22, 1899 1,239,287 Masterton Sept. 4, 1917 

